Fluid transport systems are well known and used in a number of applications. One specific application of transporting a fluid in a machine is the transportation of ink in a printer. Common examples of inks include aqueous inks and phase change or solid inks. Aqueous inks remain in a liquid form when stored prior to being used in imaging operations. Solid ink or phase change inks typically have a solid form, either as pellets or as sticks colored cyan, yellow, magenta and black. The solid ink is inserted into a printer and delivered to a melter, which melts the solid ink. The melted ink is collected in a reservoir where the melted ink continues to be heated to maintain its fluid form while awaiting subsequent use.
One or more printheads may be operatively connected to a reservoir to receive a flow of melted ink. The melted ink is ejected from a printhead by inkjet ejectors within the printhead onto a receiving medium or imaging member. The inkjet ejectors in the inkjet printing apparatus may be piezoelectric devices that eject the ink onto an imaging surface. The inkjet ejectors are selectively activated by a controller with a driving signal.
Ink supplied from a reservoir to one or more printheads may be pumped from the reservoir using various pump configurations. One configuration of a suitable pump employs rotating gears that cause ink to flow from a reservoir towards one or more printheads. Other common configurations use reciprocating members instead of rotating members to pump the melted ink from a reservoir. These pumps employ one or more seals that isolate components of the pump from direct contact with the melted ink pumped from the reservoir. These seals are typically made of elastomeric materials. The isolated pump components may also be lubricated to reduce friction during operation.
During operation, moving surfaces of the pumping mechanism that come in contact with other components in the reservoir may experience wear. Debris eroded from the worn components may damage the pumping components, and may also contaminate ink supplied to the printhead. Wear may be accelerated if there is insufficient lubrication of moving components in the pump. Additionally, certain ink chemistries used in printers may degrade the seals used in common pump configurations, causing a loss of lubricant and formation of additional debris. An ink pumping system that improves the wear characteristics of moving components and that impedes contaminants from being supplied to printheads would be beneficial.